The candidate has extensive research experience and is now completing a fellowship in infectious Diseases at the University of Rochester during which he has undertaken research in the neuropathogenesis of HIV-1 infection in the sponsor's laboratory. The MCSDA will allow him to devote >90% FTE to realize his immediate goal of expanding the scope of his research in this area, under guidance of the sponsor and collaborators, and become expert in the field. It will be a crucial step towards the long-term goal of becoming a successful, independent, full time researcher in the field of HIV-1 neuropathogenesis. The career development plan includes mechanisms for acquiring the necessary knowledge base, critical thinking, technical, presentation, and mentoring skills, ethics, and development and extension of a research project, through the proposed research, seminar series, lab and national meetings and through collaboration with Dr. Gelbard. The research will be done in the laboratory of the sponsor, Dr. Stephen Dewhurst, who maintains a vibrant research environment with adequate laboratory space and equipment and easy access to all required facilities, within a single building at the University of Rochester Medical Center. Between one- and two-thirds of children infected with HIV-1 will develop manifestations of central nervous system (CNS) disease which is accompanied by neuronal apoptosis and decreased neuronal density in discrete areas of the brain. Since HIV-1 rarely, if ever, infects neurons directly, indirect mechanisms must be involved in neuronal death. It is proposed that changes in the neuroprotective and neurotrophic properties of astrocytes during HIV-1 infection contribute to neuronal death. SPECIFIC AIM 1 of this application is to test the effects of monocyte derived factors on neuroprotective functions of astrocytes. This will involve adding conditioned media (CM) from activated, HIV-1 infected macrophages or specific candidate neurotoxins, to fetal astrocyte cultures and testing astrocyte neuroprotective functions such as neurotrophin release and glutamate transport as well as toxin production such as nitric oxide (NO) synthesis. In addition, In vivo evidence suggests that astrocytes undergo persistent "restricted" infection with HIV-1 in which HIV-1 Nef is expressed in the absence of structural proteins. SPECIFIC AIM #2 is to explore the effect of "restricted" HIV-1 infection of astrocytes on astrocyte neuroprotective functions. Primary human astrocytes will be infected with HIV-1 or transfected with Nef expressing constructs and glutamate transport, release of neurotrophic factors, or NO will be measured. Understanding the role of astrocytes in HIV-1 neuropathogenesis, specifically, what changes occur in their neuroprotective functions, may suggest interventions that could prevent or treat CNS manifestations of HIV-1 infection.